Favorable Core and Pedestal Transport Properties of the Wide Pedestal QH-Mode Regime

The high confinement Wide Pedestal Quiescent H-Mode regime ($H_{98y2}$ up to 1.6) is promising for steady burning plasma operation without ELMs and associated divertor damage, at ITER collisionalities, with nearly equal ion and electron temperatures and no net torque injected. In recent DIII-D experiments, unlike other H-Modes, confinement improves when electron cyclotron heating (ECH) replaces neutral beam power, promising for burning plasma operation. We have sustained Wide Pedestal QH-Mode for several confinement times with up to 77\% ECH power (23\% NBI) with $T_{e0} > 12$ keV.\footnote{D. R. Ernst et al., in Proc. IAEA Fusion Energy Conference, IAEA-CN-123/EX2-2, Gandhinagar, India (2018).} Fourier analysis of the ECE $T_e$ response to modulated ECH separates diffusion and convection in the electron power balance, revealing an inward core electron thermal pinch, forming an internal transport barrier (ITB) in $T_e$ as the ECH is moved on-axis. The pinch is being explored using GENE simulations (now with the first exact gyrokinetic collision operator\footnote{Q. Pan, D. R. Ernst, and P. Crandall, Phys. Plasmas {\bf 27}, 042307 (2020).}). TEM turbulence dominates, driving significant magnetic flutter transport. Even without the ITB, ion channel confinement improves in the core and pedestal as the fraction of off-axis electron heating increases. The pedestal $E_r$ well broadens and deepens, while the intensities of low and intermediate wavenumber density fluctuations respond oppositely. Wide Pedestal QH-Mode has been separately demonstrated with zero net injected NBI torque throughout. We have measured the effective intrinsic torque profile as a function of ECH power fraction (0\%, 32\%, 52\%), while simultaneously measuring electron thermal transport. The intrinsic torque density balances that from edge beam orbit loss to produce near-zero total torque density across the profile. The edge beam orbit loss torque diminishes as the fraction of ECH power increases, yet confinement improves.